Underwater depth profiles of underwater surfaces are often obtained using relatively high-power sonar signals that substantially exceed the power level of ambient noise. Such high-power sonar signals, however, have disadvantages. One such disadvantage is that high-power sonar signals are relatively easily detectable by other entities, and, under certain circumstances, it may be desirable to obtain an underwater depth profile in a manner that is not detectable by other entities. Another disadvantage is that high-power sonar signals may be harmful to aquatic life and may thus be undesirable, or even banned, in areas where aquatic life may be present.
The use of low-power sonar signals, such as sonar signals having a power level substantially equal to, or below, the power level of ambient noise, makes it difficult to distinguish between the actual sonar returns and the ambient noise, leading to inaccurate underwater depth profiles. Inaccurate underwater depth profiles can result in unexpected contact between vessels and underwater terrain or objects resulting in injuries and vessel damage.